Technical Field
The present invention relates to a robot, a robot system, a control device, and a control method.
Priority is claimed on Japanese Patent Application No. 2014-198013, filed on Sep. 29, 2014, the content of which is incorporated herein by reference.
Related Art
A control method of a robot using compliant motion control (force control) based on an output value from a force sensor has been researched and developed.
A control device or an adjustment device of a robot which determines whether the robot interferes with (that is, comes in contact with) another object based on an output value of a force sensor and which uses position control and force control described in Japanese Unexamined Patent Application, First Publication No. 2010-142909 properly based on the determination result has been known (see Japanese Unexamined Patent Application, First Publication Nos. 2010-142909 and 2011-88225).
An embedded intelligent controller which determines a control variable of impedance control while bringing an object gripped by a robot into contact with another object based on an input jog operation or the like is known (see Japanese Unexamined Patent Application, First Publication No. 2014-6566). Since this controller determines the control variable of impedance control based on movement of the robot by the jog operation or the like, it is possible to simplify a user's instruction operation and to improve convenience.
In the control device described in Japanese Unexamined Patent Application, First Publication No. 2010-142909, since the position control and the force control are switched depending on the magnitude of the output value from the force sensor relative to a predetermined value, the control for the switching is complicated. The magnitude of the force applied to the robot varies with a variation in a contact state between an object gripped by the robot and another object. However, the control device cannot change stiffness of the object gripped by the robot 20 depending on the variation in the contact state between the object gripped by the robot and another object. Accordingly, the control device has a difficulty in carrying out good assembly work.
The adjustment device described in Japanese Unexamined Patent Application, First Publication No. 2011-88225 requires learning of a neural network for determining the switching between the position control and the force control and thus has a problem in that a complicated instruction operation is required for a user.
In the controller described in Japanese Unexamined Patent Application, First Publication No. 2014-6566, since the control variable determined before causing the robot to carry out an operation cannot vary depending on the output value from the force sensor during work, the stiffness of the object gripped by the robot 20 is not changed depending on the variation in the relative position and orientation between the object gripped by the robot and another object, similarly to the control device described in Japanese Unexamined Patent Application, First Publication No. 2010-142909. Accordingly, it is difficult to carry out good assembly work.